The invention relates to automatic drip coffee makers.
A drip coffee maker is one in which coffee brew is obtained by a single pass of hot water through a quantity of coffee grounds. The hot water flow to and through the coffee grounds may be intermittent or continuous but the entire quantity of water flows through the grounds only once as opposed to a recirculating flow characteristic of percolator type coffee makers.
In the case of a typical, non-automatic drip coffee maker; coffee grounds are placed in the coffee maker, and water is heated in a separate container, such as a tea kettle, from which hot water is subsequently poured into the drip coffee maker. Manual involvement is always required at two time spaced intervals (to start the heating of the water and pouring of the same into the coffee maker approximately seven minutes later); and, in most cases, there is a third required involvement which is the placement of the coffee maker on a "keep warm" element shortly after the coffee is brewed.
In contrast, an automatic drip coffee maker is a self contained unit which heats water, flows the same across coffee grounds and keeps the brewed coffee hot. The only manual involvement is that which takes place at one point in time, i.e. commencing a brewing cycle by adding coffee grounds and water to the maker and energizing the same. The manual time requirement to commence a brewing cycle is about one minute. Completion of the brewing cycle may take from 21/2 to 15 minutes depending on the type automatic drip coffee maker employed.
Automatic drip coffee makers may, on the basis of their heated water flow systems, be categorized as being of the intermittent pumping, weir overflow or preheated displacement type.